This lorm of colitis is now considered to be one of the commonest causes of chronic diarrhoea in the dog () and appears to be much less common in the cat. However, there is a report of six cases of lymphocytic-plasmacytic colitis in cats (). It may be better described as a syndrome rather than a specific condition as there are many possible aetiological agents which may be responsible for the changes in the colon. Idiopathic colitis appears to affect any breed of dog and cat with no age or sex predisposition. However, cases appear to be more common in German Shepherd dogs. Rough Collies and Labradors. Unfortunately it is still unusual to determine the cause in the majority of cases of idiopathic colitis, hence the term, but occasionally a specific diagnosis is obtained. In this respect mycotic colitis has been recorded in cats due to Aspergillus spp.. The authors consider that dietary factors may be very important in the aetiology of colitis, because of the response noted to dietary management without drug therapy. Other aetiological agents include Trichuris vulpis infection, Salmonella spp. and Campylobacter spp. Idiopathic colitis may also develop as a sequel to gastroenteritis, secondary to small intestinal Read more […]
Gastric neoplasia is rare in dogs and cats compared with man. The types of tumour detected in small animals include polyps, adenomas, leiomyomas, adenocarcinomas and lymphosarcomas. The most frequent tumour in dogs is the adenocarcinoma and the most frequent site is the antrum or pylorus of the stomach. Lymphosarcoma is the commonest feline tumour although this is not frequently seen. Tumours frequently ulcerate so symptomatology may be similar to that observed with gastric ulceration, and endoscopically they appear very similar so histopathology of surgical biopsy is essential to differentiate which is present. Tumours have been observed more frequently in Rough Collies, Irish Setter and Terrier breeds, the mean age being 10 years and possibly more common in males than females (). Clinical diagnosis Classically there is a history of chronic vomiting, polydipsia and weight loss. The signs may appear over a short period of time or may develop more slowly over many months. The vomitus may be gastric juice and saliva or may contain food. There is no strong correlation between eating and vomiting but it certainly occurs in some individuals. Vomitus may also contain fresh or changed blood (coffee grounds) but this is not Read more […]
Progressive loss of pancreatic acinar cells ultimately leads to malabsorption due to inadequate production of digestive enzymes. The functional reserve of the pancreas is considerable, however, and signs of exocrine pancreatic insufficiency (EPI) do not occur until most of the gland has been destroyed. Although pancreatic enzymes perform essential digestive functions, alternative pathways of digestion for some nutrients do exist. Following experimental exclusion of pancreatic secretion from the intestine, dogs can still absorb up to 63% of ingested protein and 84% of ingested fat. This residual enzyme activity probably originates from lingual and/or gastric lipases and gastric pepsins, from intestinal mucosal esterases and peptidases, and, in young animals, from bile salt-activated lipase in milk. Nonetheless, when exocrine pancreatic function is severely impaired, these alternative routes of digestion are inadequate and clinical signs of malabsorption occur. Feline EPI is much less common than EPI in dogs, but development of a reliable test for fTLI has shown the disease to be far more prevalent than previously realized. Aetiology Spontaneous development of pancreatic acinar atrophy (PAA) in previously healthy adult Read more […]
Disease of Alimentary System Colitis The colon in the lower bowel is primarily concerned with reabsorption of water as the products of digestion move down the alimentary tract. Any influence which leaves water within the bowel will contribute to the water content of the dog’s motions, which can vary from slightly wet faeces to frank diarrhoea if the colon becomes inflamed. Any blood present is usually fresh, staining the motions red, and often there is straining, discomfort and a degree of pain. Motions may contain mucus, with little evidence of unabsorbed fat. Veterinary examination is necessary to establish the several clinical conditions. Boxers appear to have a predisposition to two types of ulcerative colitis: Histiocytic Ulcerative Colitis, which does not respond well to treatment; and Idiopathic Ulcerative Colitis, which may recover with appropriate treatment. Dietary treatment has little effect on lower bowel conditions; the underlying cause for colitis must be established. Colitis, inflammation of the large intestine, is responsible for half of all cases of recurrent or Persistent diarrhoea in the dog. Inflammation of the colon lining prevents residual vvater from being absorbed efficiently, thus creating this Read more […]
Most breeders would like to think that they could eliminate/ eradicate a defect. Generally this is not feasible. If we are faced with a dominant gene like VWD we could on testing dogs, cull from breeding all those with the condition and thus eliminate the gene in one generation. For this reason, few defects in the dog are dominant as they have long been eliminated. With a recessive gene, we only identify it when the affected animal crops up. If we take this as being aa, then we can show that both normal parents were actually Aa. Discarding the affected animal helps but discarding the parents helps more so. Unfortunately, as vve discard more Aa and aa animals, we find fewer and fewer cropping up. Many Aa animals are mated to AA stock and thus produce only AA and Aa offspring but no aa cases. We thus keep the “a” allele hidden in the population and make aa cases rarer, but they can still crop up, often after long years of apparent freedom. A recessive allele cannot be eliminated unless a technique exists which enables identification of Aa types from AA animals. Frequently this is not possible. One identifies an Aa animal only vvhen it produces aa offspring. Combating a recessive defect usually entails trying to establish Read more […]
Some alleles act in such a way as to bring about variable effects, depending on several factors, including the rest of the animal’s genetic make-up. One recessive gene causes the condition known as Collie Eye Anomaly (CEA), seen in sheepdog breeds such as the Rough Collie, Shetland Sheepdog and, to a lesser extent, the Border Collie. Dogs carrying the combination cea cea exhibit the disease, which may vary from total blindness with detached retinas to almost unimpaired vision but with an abnormal eye picture when seen through an ophthalmoscope. The normal dog (CEA CEA) and the carrier (CEA cea) will have correct vision. Another type of inherited disorder is caused by incomplete penetrance, in which a particular gene, usually dominant, fails to express its presence in the phenotype, as in Centralized Progressive Retinal Atrophy (CPRA) in Labradors. This eye disease is thought to be so dominant that the presence of only one allele, CP, will cause impaired vision. In most cases CP CP and CP cp animals are affected and only cp cp animals have unimpaired vision. However in some 20 per cent the CP cp heterozygote appears phenotypically normal, and the gene is therefore said to show 80 per cent penetrance.
There are three basic skull shapes in dogs: 1. Dolichocephalic – Long-nosed breeds like the Rough collie, Afghan Hound, Doberman and Fox Terrier. 2. Brachycephalic – Short, snub-nosed breeds like the Pug, Bulldog and Pekingese. 3. Mesocephalic – A group including dogs which fall between the other two extremes. Parts of the skull The features of the skull tend to vary with the overall shape and type of the skull. The eye: The eye sits in the space called the orbit with in the zygomatic arch. The two zygomatic arches govern the total width of the skull. They vary in shape between the breeds – long-nosed breeds have a fairly straight arch while in short-nosed breeds it is very curved. The jaw:The shape of the jaw varies quite considerably between breeds. The official breeds standards include requirements for the “bite” of each dog. The jaw muscles are very powerful. It is said that a 20 kg mongrel can exert a bite of 165 kg; the pressure of an average human bite is 20-30 kg. The cranium: The upper part of the dog’s skull, it houses the brain and also varies between breeds. In the Chihuahua, a high-domed shape has been specially selected over years of breeding. Unfortunately this has led in certain cases to Read more […]